Portable power bank



FIG. 1 is a top perspective view of a portable power bank showing the new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof; and,

FIG. 9 is an enlarged view of the portion 9 shown in FIG. 1 .

The broken lines in the drawings depict portions of the portable power bank that form no part of the claimed design. 

CLAIM The ornamental design for a portable power bank, as shown and described. 